- Construction of Highly Functionalized Xanthones via Rh-Catalyzed Cascade C-H Activation/ O-Annulation
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A facile and efficient strategy for obtaining functionalized and multihydroxylated xanthones via Rh catalysis under redox-neutral conditions is developed. Diverse salicylaldehydes bearing heterocycles, aromatics, and fused aromatics can be rapidly coupled with 1,4-benzoquinones or 1,4-hydroquinones to afford valuable xanthones via cascade C-H/O-H functionalization and annulation. This protocol provides a rapid synthetic approach to obtain biologically active materials through late-stage functionalization and prepares natural products such as subelliptenone, pruniflorone N, and ravenelin.
- Nale, Sagar D.,Maiti, Debabrata,Lee, Yong Rok
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supporting information
p. 2465 - 2470
(2021/04/05)
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- Flavonoid analogues as urease inhibitors: Synthesis, biological evaluation, molecular docking studies and in-silico ADME evaluation
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A series of novel flavonoid analogues were designed and synthesized. The aimed compounds for urease inhibitory activities were clearly superior to the control drug thiourea (more than 10 times). Among these compounds, L2 (IC50 = 1.343 μM) and L12 (IC50 = 1.207 μM) exhibited the most excellent urease inhibitory activity in vitro. The molecular dockings of L2, L12 and L22 into urease were performed to explore the binding modes and their structure-activity relationship. Furthermore, these aimed compounds showed good druggable properties.
- Liu, Honghui,Wang, Yan,Lv, Mingxia,Luo, Yi,Liu, Bu-Ming,Huang, Yan,Wang, Mian,Wang, Jianyi
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- Synthesis and biological evaluation of flavone-8-acrylamide derivatives as potential multi-target-directed anti Alzheimer agents and investigation of binding mechanism with acetylcholinesterase
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In a search for novel multifunctional anti-Alzheimer agents, a congeneric set of seventeen flavone-8-acrylamide derivatives (8a─q)were synthesized and evaluated for their cholinesterase inhibitory, antioxidant, neuroprotective and modulation of Aβ aggregation activities. The target compounds showed effective and selective inhibitory activity against the AChE over BuChE. In addition, the target compounds also showed moderate anti-oxidant activity and strong neuroprotective capacities, and accelerated dosage-dependently the Aβ aggregation. Also, we presented here a complete study on the interaction of 8a, 8d, 8e, 8h and 8i with AChE. Through fluorescence emission studies, the binding sites number found to be 1, binding constants were calculated as 2.04 × 104, 2.22 × 104, 1.18 × 104, 9.8 × 103 and 3.2 × 104 M?1 and free energy change as ?5.83, ?5.91, ?5.51, ?5.41 and ?6.12 kcal M?1 at 25 °C which were well agreed with the computational calculations indicating a strong binding affinity of flavones and AChE. Furthermore, the CD studies revealed that the secondary structure of AChE became partly unfolded upon binding with 8a, 8d, 8e, 8h and 8i.
- Shaik, Jeelan Basha,Yeggoni, Daniel Pushparaju,Kandrakonda, Yelamanda Rao,Penumala, Mohan,Zinka, Raveendra Babu,Kotapati, Kasi Viswanath,Darla, Mark Manidhar,Ampasala, Dinakara Rao,Subramanyam, Rajagopal,Amooru, Damu Gangaiah
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- New Flavone-Cyanoacetamide Hybrids with a Combination of Cholinergic, Antioxidant, Modulation of β-Amyloid Aggregation, and Neuroprotection Properties as Innovative Multifunctional Therapeutic Candidates for Alzheimer's Disease and Unraveling Their Mechanism of Action with Acetylcholinesterase
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In line with the modern multi-target-directed ligand paradigm of Alzheimer's disease (AD), a series of 19 compounds composed of flavone and cyanoacetamide groups have been synthesized and evaluated as multifunctional agents against AD. Biological evaluation demonstrated that compounds 7j, 7n, 7o, 7r, and 7s exhibited excellent inhibitory potency (AChE, IC50 of 0.271 ± 0.012 to 1.006 ± 0.075 μM) and good selectivity toward acetylcholinesterase, significant antioxidant activity, good modulation effects on self-induced Aβ aggregation, low cytotoxicity, and neuroprotection in human neuroblastoma SK-N-SH cells. Further, an inclusive study on the interaction of 7j, 7n, 7o, 7r, and 7s with AChE at physiological pH 7.2 using fluorescence, circular dichroism, and molecular docking methods suggested that these derivatives bind strongly to the peripheral anionic site of AChE mostly through hydrophobic interactions. Overall, the multifunctional profiles and strong AChE binding affinity highlight these compounds as promising prototypes for further pursuit of innovative multifunctional drugs for AD.
- Basha, Shaik Jeelan,Mohan, Penumala,Yeggoni, Daniel Pushparaju,Babu, Zinka Raveendra,Kumar, Palaka Bhagath,Rao, Ampasala Dinakara,Subramanyam, Rajagopal,Damu, Amooru Gangaiah
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p. 2206 - 2223
(2018/05/23)
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- Synthesis and biological evaluation of novel flavone/triazole/benzimidazole hybrids and flavone/isoxazole-annulated heterocycles as antiproliferative and antimycobacterial agents
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Abstract: A series of new flavone/isoxazole fused heterocycles 5a–f and flavone/1,2,3-triazole/benzimidazole hybrid heterocycles compounds 7a–t were synthesized via an intramolecular cyclization and Cu(I)-catalyzed click 1,3-dipolar cycloaddition. The pro
- Rao, Yerrabelly Jayaprakash,Sowjanya, Thummala,Thirupathi, Gogula,Murthy, Nandula Yadagiri Sreenivasa,Kotapalli, Sudha Sravanti
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- Synthesis and antiproliferative activity of some dihydro-1 H-furo[2,3-c]pyrazole-Flavone hybrids
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A new series of dihydro-1 H-furo[2,3-c]pyrazole-flavone hybrids were synthesized from one-pot four-component reaction of β-keto ester (1), hydrazine (2),7-hydroxy 8-formyl flavones (3), pyridiniumylide (4) in presence of NEt3 as catalyst under ethanol reflux conditions and their antiproliferative properties were evaluated against human cancer cell lines, namely, laryngeal carcinoma (Hep2), lung adenocarcinoma (A549) and cervical cancer (HeLa). The best among them, furo[2,3-c]pyrazole-flavone with C4′-methoxy substitution was selected for further structure activity relationship (SAR) studies. Among the derivatives, (4S,5S)-ethyl 4-(7-hydroxy-5-methoxy-4-oxo-2-(2,4,6-trimethoxyphenyl)-4H-chromen-8-yl)-3-methyl-4,5-dihydro-1 H-furo[2,3-c]pyrazole-5-carboxylate (8r) showed most potent cytotoxic activity against all three cancer cell lines. Toxicity studies revealed that the dihydro-1H-furo[2,3-c]pyrazole-flavones are specifically target the cancer cell lines.
- Tangeti, Venkata Swamy,Vasundhara,Satyanarayana,Pavan Kumar, Kaja Srinivas
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p. 1525 - 1532
(2017/05/29)
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- A tandem synthesis of 3-aroylcoumarinoflavones catalyzed by l-proline and their antioxidant activity
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A facile, convenient, efficient and high-yielding synthesis of 3-aroylcoumarinoflavones has been developed by the condensation of easily synthesized 7-hydroxy-8-formylflavones and benzoyl acetonitriles in the presence of catalytic amount of l-proline in e
- Thirupathi,Yadaiah Goud,Hemasri,Suban Ali, Md.,Jayaprakash Rao
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p. 477 - 483
(2017/01/10)
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- Synthesis of novel substituted pyrano annulated flavones
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A simple and efficient one pot method has been developed for the synthesis of some new functionalized pyrano fused flavone derivatives, alkyl 4,8-dioxo-2-phenyl-4,8-dihydropyrano[2,3-f]chromene-10-carboxylates and dialkyl 4-oxo-2-phenyl-4,8-dihydropyrano[2,3-f]chromene-8,9-dicarboxylates, from 7-hydroxy flavones and 7-hydroxy 8-formyl flavones using dialkylacetalynedicarboxylates in the presence of triphenyl phosphine. The structures of all synthesized compounds were elucidated by FT-IR, 1H and 13C NMR and Mass spectral analysis.
- Jayaprakash Rao,Thirupathi,Prasad Rao, Ch.,Hemasri
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p. 1126 - 1131
(2016/07/06)
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- Single and double intramolecular proton transfers in the electronically excited state of flavone derivatives
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In an attempt to create a flavone derivative able to take part in Excited State Intramolecular Double Proton Transfer (ESIDPT), we synthesized two carbonyl derivatives of 3,7-dihydroxyflavone, both containing two different proton-transfer sites as well as related carbonyl derivatives of 3-hydroxyflavone and 7-hydroxyflavone. All the examined hydroxyflavones were found to participate in the Excited State Intramolecular Proton Transfer (ESIPT). ESIPT which involves 3-hydroxyl and 4-carbonyl groups was found to have a higher barrier compared to ESIPT involving 7-hydroxyl and 6/8-carbonyl fragments. According to the data presented, 3,7-dihydroxy-2-phenyl-6-(3-phenylpropanoyl)-4H-chromen-4-one undergoes a two-stage ESIDPT with formation of an intermediate tautomer. This kind of ESIDPT leads to a tautomeric form with an abnormally low rate of radiative deactivation of the excited state, which conditions low fluorescence quantum yield. The behavior of 3,7-dihydroxy-4-oxo-2-phenyl-4H-chromene-8-carbaldehyde in the electronically excited state is similar to 3-hydroxyflavone derivatives, thus we conclude the occurrence of a single ESIPT in this compound.
- Serdiuk,Roshal
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p. 102191 - 102203
(2015/12/11)
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- Synthesis of 3-aroylcoumarin-flavone hybrids
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A facile two step synthesis of 3-aroylcoumarin-flavone hybrids was achieved from 7-hydroxyflavone and α- oxoketene dithioacetals. In the first step 7-hydroxyflavone was regioselectively formylated under Duff reaction conditions. Resulting 8-formyl-7-hydro
- Rao, Hulluru S.P.,Tangeti, Venkata S.
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experimental part
p. 218 - 220
(2012/07/14)
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- Facile synthesis of 9-acetyl/formyl/cyano-substituted pyrano[2,3-f]flavones and chromones using the baylis-hillman reaction
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Condensation of 8-formyl-7-hydroxyflavones (2a-f) and 8-formyl-7-hydroxy-2- (2'-furyl)-3-methylchromone (2g) with methyl vinyl ketone (3), acrolein (4), and acrylonitrile (5) in the presence of diazabicyclo[2.2.2]octane (DABCO) under an N2 atmosphere at room temperature using Baylis-Hillman reaction conditions afforded 9-acetyl/formyl/cyano-substituted pyrano2,3-f]flavones (6a-f, 7a-f, 8a-f) and chromones (6g, 7g, 8g).
- Reddy, S. Satyanarayana,Krupadanam, G. L. David
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experimental part
p. 1292 - 1304
(2010/06/20)
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- Facile synthesis of 7-methoxy-2-aryl-3-phenyl/or-H-8-[2-(4,6-dimethyl-3,5- dicarbethoxy-pyridyl)]-4H-1-benzopyran-4-ones
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Condensation of 8-formyl-7-methoxy-2-phenyl-4H-1-benzopyran-4-ones (5a-f) with ethyl-3-aminocrotonate (6) in glacial acetic acid under Hantzsch conditions afforded 7-methoxy-2-aryl-3-phenyl/or-H-8-[2-(4,6-dimethyl-3,5-dicarbethoxy- pyridyl)]-4H-1-benzopyran-4-ones (7a-f) in good yields. Copyright Taylor & Francis Group, LLC.
- Soni, Anil Kumar,Krupadanam, G. L. David,Srimannarayana
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p. 795 - 804
(2007/10/03)
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